The simplest way would be to send the signal from the macbook into 2 channels of the desk.
Adjust the audio files so that the track comes out of the left channel, and the click out of the right.
Attach your IEMs into the aux channels and send the click to the Aux but not front of house.
My party band has a 16 channel, 6 Aux mixer. There are 4 of us so Aux 1-4 gives us an individual monitor mix, and the remaining 2 run to a delay & reverb.
IEMs can run into a lot of cash though!